US and World Avalanche Accident Statistics

The Colorado Avalanche Information Center (CAIC) has a detailed database of the US and World Avalanche Accident Statistics. Their statistics and graphs are very comprehensive and separate accidents by year, state, and user groups. They also provide written accident reports which can be quite interesting and informative.

Local Avalanche Accident Reports

Posted below are accident reports from our advisory area for the current season.

MOUNT TWO TOP AVALANCHE ACCIDENT

TARGHEE NATIONAL FOREST

11 FEBRUARY 2009

SYNOPSIS:

A group of six snowmobilers from Yakima, WA was riding on Mount Two Top near the town of West Yellowstone when one of the riders triggered an avalanche. He was caught, buried, and seriously injured. The avalanche released on a northeast facing, wind loaded slope. The average slope angle ranged from 26 to 30 degrees but was 43 degrees just under the cornice. The avalanche was estimated to be 100 ft wide by 150 ft vertical and the slope distance was 350 ft. US Classification of the avalanche is SS-AM-R1-D2-I.

GPS Coordinates for the slope are:

N 44.61809

W 111.24502

Elevation: 8200 ft, Aspect: 56 degrees NE, Average slope angle: 26-30 degrees

Alpha angle at toe of debris: 25 degrees

PHOTOS:

http://www.mtavalanche.com/photos/photos.php

VIDEO CLIP:

http://www.youtube.com/watch?v=DkuLXIshq94

WEATHER:

Wind data are taken from a weather station operated and maintained by the Gallatin National Forest Avalanche Center approximately 7 miles northwest at an elevation of 8243 ft. Snowfall data are taken from the Madison Plateau Snotel Site at an elevation of 7750 ft.

During the previous 24 hours approximately 0.2 in of snow water equivalent fell and winds blew 7-14 mph with gust of 11-22 mph from the south and southwest. These winds readily transported snow and deposited it on the slope that slid. During the investigation on January 12, winds had deposited more snow and the crown of the avalanche was no longer visible.

AVALANCHE:

This information was gathered by talking with Tim Campbell from the Hebgen Lake Ranger District who was on scene during the rescue.

The victim was riding with 5 others. All six were carrying appropriate avalanche rescue gear. At approximately 1200 the victim and another member of the group were riding on the slope at the same time. As the victim was near the apex of his path, the slope fractured and he was carried approximately 100 ft downhill. He impacted several trees and was buried with only his hand exposed. The other rider was on the same slope but on the edge of the avalanche. Members of the party began an immediately rescue. They were unable to detect a signal from the victim’s beacon, but the saw his hand sticking out of the snow. They dug him out. He was breathing but seriously injured. They moved him further down the slope fearing additional avalanche hazard.

SEARCH AND RESCUE:

Search and Rescue from West Yellowstone was notified of the avalanche and arrived at approximately 1300 with a rescue sled. Because the victim had been moved down slope by his partners, the rescue sled was able to be parked very close to the victim. He was transported and transferred to an ambulance by 1530.

SNOWPACK:

Doug Chabot and Mark Staples investigated the avalanche with Ron Naber and Tim Campbell. A layer of surface hoar crystals about 4-6 mm in size was found 38 cm (15 in) deep under a 4 fingers hardness slab and on top of 1 finger hardness snow. Near the flank of the avalanche, this layer easily fractured in stability tests (CT 11/12 Q1) and was evident as a noticeable stripe through the snow pit wall.

This avalanche occurred in the Targhee National Forest in Idaho approximately 0.4 miles outside the advisory area; however, this area has a very similar snowpack to the portion of the advisory area near West Yellowstone.

Please contact me for more information or if you have any questions. I can be reached at 406-587-6984 or mstaples@fs.fed.us

Mark Staples

Avalanche Specialist

Gallatin National Forest Avalanche Center

www.mtavalanche.com

CROWN BUTTE AVALANCHE FATALITY

17 JANUARY 2009

SYNOPSIS:

Saturday afternoon at 1730 MST a group of five snowmobilers was riding in the mountains near Cooke City, MT just north of Daisy Pass. The victim was climbing a steep, north northeast facing slope on Crown Butte when he got stuck. While working to free his sled, it began tumbling down the slope. It tumbled 3-4 times before impacting a rock 50-100 ft below him. The slope then fractured about 75 ft above him. The resulting avalanche was estimated to be 300 ft wide and 1000 ft vertical. The crown height ranged from 2 ft to 15 ft, and the run out angle was 28 degrees. The four members in his party immediately conducted a very thorough beacon search but could not detect a signal. A search continued the following day, and he was located with an avalanche dog. He was found beneath 3 feet of snow with his beacon turned off. His snowmobile was partially buried approximately 50 ft downhill. US Classification of the avalanche is HS-AM-R5-D4-O.

GPS Coordinates from the toe of the debris:

N 45.05750

W 109.96004

Elevation of debris: 9,300 ft

Elevation of crown: 10,200 ft

Slope Aspect: 20 degrees NNE

Slope Angle in starting zone: 37-40 degrees

Photos of the avalanche can be seen at:

http://www.mtavalanche.com/photos/photo_popup.php?photo=1232325322

http://www.mtavalanche.com/photos/photo_popup.php?photo=1232324991

WEATHER:

The weather data for this incident is from the Fisher Creek Snotel Site located approximately 1.5 miles northeast of the avalanche.

The last precipitation in the mountains near Cooke City occurred on Monday, January 12. Since daily advisories began on December 12, 2008, this area received snow on 30 out of 37 days and significant winds occurred during much of this time. Three days prior to this avalanche a large ridge of high pressure moved over the advisory area producing temperatures above freezing and clear skies on the day of the accident. The weekend of this accident was the first full weekend with clear weather since early December.

SNOWPACK:

Snow depths at the accident site were highly variable; however, faceted snow crystals at or near the ground have been found on all aspects in this area. This layer of facets has been responsible for many natural and human triggered avalanches on nearby mountains such as Henderson and Scotch Bonnet. With nearly constant snowfall since this layer was buried in early December, no other weak layers have formed in the snowpack. This layer of facets was found with old, pencil hardness, wind slabs on top during our investigation on Sunday, January 18. The slope that slid faces north north east and receives wind drifted snow from westerly winds that load this slope both near the top and along one side.

The avalanche danger in the mountains north of Cooke City on the day of the accident was rated CONSIDERABLE on all slopes steeper than 35 degrees.

SEARCH AND RESCUE:

The avalanche happened at approximately 1730. The members of the party immediately conducted a through beacon search but detected no signal. One of them activated the 911 feature on a SPOT device. This action notified the International Response Center which contacted Carbon County who contacted Yellowstone National Park who contacted Livingston Dispatch. A Hasty Team provided the initial response that evening and did not locate the victim. The following day more rescuers were mobilized for probe teams, and two avalanche dog teams responded. By afternoon one of the dogs indicated a possible location, the handler probed in that spot, and she found him. He was extricated from the debris, packaged, and taken to the firehall in Cooke City.

Please contact me for more information or if you have any questions. I can be reached at 406-587-6984 or mstaples@fs.fed.us

Mark Staples

Avalanche Specialist

Gallatin National Forest Avalanche Center

www.mtavalanche.com

________________________________________________________________________

________________________________________________________________________

GRAVELLY RANGE AVALANCHE FATALITY

Beaverhead-Deerlodge NF

17 JANUARY 2009

SYNOPSIS:

A group of 14 snowmobilers went into the Black Butte area of the Gravelly Range when one of the riders triggered an avalanche. He was caught and fatally buried. The avalanche released on an east facing, wind-loaded slope. The slope angle was approximately 35-40 degrees with the crown face 1-4 feet deep, averaging 2 feet. The avalanche was estimated to be 200 feet wide and 75 feet vertical. US Classification of the avalanche is HS-AM-D2-R4-O.

GPS Coordinates for the slope is

N 44.54’ 45”

W 111.53’ 59.2”

Elevation of crown is 9,000 feet.

PHOTOS:

http://mtavalanche.com/data/images/1232281305.jpg

http://mtavalanche.com/data/images/1232280870.jpg

http://mtavalanche.com/data/images/1232281037.jpg

VIDEO CLIP:

http://www.youtube.com/watch?v=WFMi1gtaH-o

WEATHER:

The snowfall and temperature data for this incident is from the Carrot Basin SNOTEL site approximately 30 miles east of the avalanche. Wind data is from the Yellowstone Club 30 miles to the northeast.

Saturday, January 17th was a clear, calm day. The temperature was 36F at 9,000’ feet at the time of the accident. The previous four days had no significant snowfall and winds were out of the west to northwest averaging 15-25 mph.

AVALANCHE:

This information was gathered by talking with JP a member of the group and first on the avalanche scene.

The victim, KH (50), was riding with a group of friends. There were 14 in the party and were very familiar with the terrain. They were all expert riders and had avalanche rescue gear. A few of the riders had taken avalanche courses from the GNFAC and some had read the Avalanche Advisory that morning. They saw an avalanche on Black Butte on the ride in and confirmed the weak, faceted snow at the ground every time they got stuck. As a group they decided to just boondock and stick to smaller slopes in the trees.

At approximately 1130 the group stopped in a meadow and noticed KH was missing. JP went looking for him. He found the track not far from the meadow. A little further along he saw the crown of the avalanche and then the snowmobile sticking out of the toe of the debris. At KH’s sled he switched his beacon to receive an immediately picked up a signal and pinpointed him. He started digging and uncovered KH’s head about 1-2 feet under the surface. He was in a sitting position with his back to the machine. JP estimates that 10-15 minutes elapsed from the time KH wet missing until he was found. The others arrived and he was completely extricated by 1150. He was unconscious and pulseless and they began CPR. At 1210 they activated their SPOT messenger which notified a 911 call center. CPR continued for the next 2 ½ hours. KH had good color throughout so they knew they were doing effective compressions. At 1435 they suspended CPR.

The location of the avalanche was approximately 25 miles of riding from the Lyons Bridge trailhead. It was far from any trail and in the heart of the Gravelly Range in the remote backcountry. With minimal stops it was a 90-minute ride back to the trailhead.

SEARCH AND RESCUE:

The 911 SPOT message was relayed to Madison County SAR. Soon after receiving it they asked for assistance from Gallatin County SAR since they have a Heli-Rescue Team. Karl Birkeland and I met the helicopter at the Gallatin County Fairgrounds and flew to the scene. We arrived at approximately 1530 and within 15 minutes had the victim placed in a net for long-line helicopter extrication. While he was being flown out I interviewed the party while Karl looked at the avalanche. The helicopter returned at 1615 to pick up Karl. I rode the victims snowmobile out to the trailhead arriving at 1800.

SNOWPACK:

Karl Birkeland investigated the avalanche and found the snowpack structure to be very similar to the nearby Madison Range. A pencil hardness wind slab was sitting on a layer of faceted snow. The avalanche broke within these facets and propagated for 200 feet, much further than its vertical relief if 75 feet. The slope got strongly cross loaded from south winds over the course of the season.

This avalanche is not in our advisory area. However, given the similarity of the snowpack it’s worth noting that the avalanche danger in the Madison Range, 15 miles to the east, was rated MODERATE.

Please contact me for more information or if you have any questions. I can be reached at 406-587-6984 or dchabot@fs.fed.us

Doug Chabot

Director

Gallatin National Forest Avalanche Center

www.mtavalanche.com

_______________________________________________________________________

_______________________________________________________________________

MT. JEFFERSON AVALANCHE FATALITY

Centennial Mountains, Beaverhead-Deerlodge National Forest

17 January 2009

This accident synopsis was gathered from a Seattle Post Intelligencer article and a detailed interview with a rescuer, Sean. The article can be found here: http://seattlepi.nwsource.com/local/6420ap_id_avalanche_death.html

On Saturday, January 17th, 2009, 21 y.o. snowmobiler Joshua Jenkins from Idaho Falls, ID was killed in an avalanche while highmarking in the Hell Roaring drainage south of Mt Jefferson, MT. His partners were not watching him at the time and no one had shovels or probes. The rider was a 21 y.o. male from Idaho Falls. His head was buried 6-7 feet deep and was dug out in 20 minutes using a beacon to locate him.

Sean was not a member of the party that triggered the avalanche. He was out riding with his father and friends. His father stopped him and said he had just seen an avalanche release on Mt. Jefferson. They both could see the crown. They rode to the site and estimated the slide was 1000’ long, 50 feet wide and had debris 14-20’ deep. It took Sean 8 minutes from the time they saw the slide until they arrived on scene.

There were 4-5 people already on the debris walking around. Sean did not notice any sense of urgency and thought that perhaps they were only looking for a buried sled. One of them yelled to Sean that they needed a probe. The folks on the debris were walking in a tight 5-10 foot circle when someone yelled ‘I found him!” It was obvious to Sean that they were looking for someone, and a rescuer had not turned off his beacon creating confusion. No one on the scene had taken charge and it showed.

Sean was responsible for half the rescue gear on the hill at that time. He had 1 of the 2 probes and 1 of the 2 shovels. The group was completely unprepared and showed no signs of training.

Sean told them to shut off their beacons because they were following one another. Once this was done they were able to locate the sled but unable to pin point Joshua. Unwilling to wait Sean turned his beacon to “receive” and quickly pinpointed Joshua. Digging as fast as they could they found him underneath the sled. It took 6 to 7 people to lift sled out. They then dug down and pulled Joshua out, but CPR was too late.

By the end of the rescue about 15 people were on scene helping out. Although he was found within 20 minutes, a deep burial is hard to survive.

From Sean’s email about the avalanche conditions:

“That morning my dad and the others in my group thought that the prevailing snow conditions were safe and not going to produce an avalanche. I knew it was capable and that the slide would be large and destructive if released (thanks to several avalanche center recordings). Looking back I would not have thought that it would have been the slope to slide. It is a south west facing slope that receives a lot of sun throughout the day. It is not a wind loaded slope and it had a thinner snow pack. This taught me that no matter what the conditions are any slope can slide.”

Sean took two of our 2-day Avalanche Awareness for Snowmobilers courses one in 2005 and the other in 2006. Mt Jefferson is located about 30 miles west of West Yellowstone, MT and is not in our advisory area.

Report compiled by:

Doug Chabot

Director, Gallatin National Forest Avalanche Center

dchabot@fs.fed.us

406-587-6984